Colour is a decisive aspect when judging the beauty of a diamond. The purer and more colourless the diamond, the greater its rarity and value. Not only this, but its capacity to reflect and refract light ensuring you have a glistening diamond forever. White diamonds come in various shades and may appear colourless to the untrained eye, however on closer inspection they will almost certainly contain very slight traces of brown, yellow or grey. Diamonds are graded on a colour scale established by the Gemmological Institute of America (GIA). This scale ranges from D (colourless) and moves through the alphabet to Z. The price difference even between a single colour grade can be significant.